我有一个产品搜索小部件，当您选择某些产品时，会显示一个隐藏字段。我想在我的小部件选项中设置一个自定义类别，然后用于显示隐藏字段。

当我将父category\\u id手动添加到代码中时，前端可以100%工作。现在我只需要在后端设置category选项。

这是我目前拥有的，但它不起作用，因为它没有存储所做的选择。我省略了搜索表单，因为它没有使用任何小部件选项。

class Equipment_Search extends WP_Widget {

    function Equipment_Search() {
        $widget_ops = array( \'classname\' => \'agriquip\', \'description\' => __(\'Displays the Equipment Search Form\', \'agriquip\') );
        $control_ops = array( \'width\' => 200, \'height\' => 350, \'id_base\' => \'agriquip-widget\' );
        $this->WP_Widget( \'agriquip-widget\', __(\'Equipment Search\', \'agriquip\'), $widget_ops, $control_ops );
    }

    function widget( $args, $instance ) {
        extract( $args );

        $title = apply_filters(\'widget_title\', $instance[\'title\'] );
        $tract_id = isset( $instance[\'exc_equipment_cat\'] ) ? $instance[\'exc_equipment_cat\'] : false;   
        $tract = wp_list_pluck(get_terms(\'exc_equipment_cat\', array(\'parent\' => 3)), \'slug\');
        $tractparent = get_term_by(\'id\',\'3\', \'exc_equipment_cat\');
        $tractparent = $tractparent->slug; 


        echo $before_widget;
echo $after_widget;
    }

    function update( $new_instance, $old_instance ) {
        $instance = $old_instance;

        //Strip tags from title and name to remove HTML 
        $instance[\'title\'] = strip_tags( $new_instance[\'title\'] );
        $instance[\'exc_equipment_cat\'] = $new_instance[\'exc_equipment_cat\'] ? 1 : 0;

        return $instance;
    }

    function form( $instance ) {

        //Set up some default widget settings.
        $defaults = array( \'title\' => __(\'Equipment Search\', \'agriquip\'), \'exc_equipment_cat\' => \'-1\');
        $instance = wp_parse_args( (array) $instance, $defaults ); ?>

        <p>
            <label for="<?php echo $this->get_field_id( \'title\' ); ?>"><?php _e(\'Title:\', \'agriquip\'); ?></label>
            <input id="<?php echo $this->get_field_id( \'title\' ); ?>" name="<?php echo $this->get_field_name( \'title\' ); ?>" value="<?php echo $instance[\'title\']; ?>" class="widefat" />
        </p>

            <form method="post" action="">
                <label for="exc_equipment_cat">Category to use with Kw Options</label>
                <?php
                        $dropdown_args = array(
                            \'taxonomy\'          => \'exc_equipment_cat\',
                            \'name\'              => $this->get_field_name(\'exc_equipment_cat\'),
                            \'show_count\'        => 1,
                            \'orderby\'           => \'name\',
                            \'hierarchical\'      => true,
                            \'echo\'              => 0,
                            \'depth\'             => 1,
                            \'show_option_none\'  => \'Select Category\',
                            \'selected\'          => (int)$instance[\'exc_equipment_cat\'],
                            );
                        wp_dropdown_categories(apply_filters(\'widget_categories_dropdown_args\', $dropdown_args));
                        $select = wp_dropdown_categories(apply_filters(\'widget_categories_dropdown_args\', $dropdown_args));
                        $select = preg_replace("#<select([^>]*)>#", "<select$1 class=\'widefat\'>", $select);
                    echo $select;
                ?>  
            </form>


    <?php
    }